Synchronization Signal Block Reception in Wireless Communications

ABSTRACT

A user equipment (UE) monitors for a synchronization signal block (SSB) to synchronize with a cell of a network. The UE monitors a frequency band during a discovery reference signal (DRS) window for a synchronization signal block (SSB) transmitted by a cell of the network, determines an SSB index based on information received from the cell of the network and synchronizes with the cell based on the SSB index.

BACKGROUND

A user equipment (UE) may scan one or more frequency bands and monitorfor synchronization information broadcast by a cell of the network. Forexample, the cell may transmit multiple synchronization signal blocks(SSBs) within a particular time window. Once detected, the UE mayacquire time and frequency synchronization with the cell using thesynchronization information.

In some networks, signaling between the UE and a cell of the network maybe performed over the unlicensed spectrum. The unlicensed spectrum isshared by different devices using different communication protocols.Access to the unlicensed spectrum may implicate various regulationsand/or standards. For instance, Listen-Before-Talk (LBT) may beimplemented in accordance with these regulations and/or standards toaccess the unlicensed spectrum for communications.

For unlicensed operation, the number of candidate SSB positions may beincreased to account for LBT failure. However, conventional techniquesfor acquiring cell timing are unable to handle the increase in candidateSSB positions. Accordingly, there is a need for mechanisms configured toenable the UE to determine cell timing when the number of candidate SSBpositions is increased for unlicensed operation.

SUMMARY

Some exemplary embodiments are related to a baseband processorconfigured to perform operations. The operations include monitoring afrequency band during a discovery reference signal (DRS) window for asynchronization signal block (SSB) transmitted by a cell of the network,determining an SSB index based on information received from the cell ofthe network and synchronizing with the cell based on the SSB index.

Other exemplary embodiments are related to a user equipment (UE)including a transceiver configured to communicate with multiple networksand a processor communicatively coupled to the transceiver andconfigured to perform operations. The operations include monitoring afrequency band during a discovery reference signal (DRS) window for asynchronization signal block (SSB) transmitted by a cell of the network,determining an SSB index based on information received from the cell ofthe network and synchronizing with the cell based on the SSB index.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary network arrangement according to variousexemplary embodiments.

FIG. 2 shows an exemplary user equipment (UE) according to variousexemplary embodiments.

FIG. 3 shows an example of an extended DRS window according to variousexemplary embodiments according to various exemplary embodiments.

FIG. 4 illustrates an example of splitting a synchronization signalblock (SSB) index into two parts that are to be jointly transmittedusing demodulation reference signal (DM-RS) and physical broadcastchannel (PBCH) channels according to various exemplary embodiments.

FIG. 5 shows a table that illustrates how a part of the SSB index may beimplicitly signaled based on the symbol location of the primarysynchronization signal (PSS) and the secondary synchronization symbol(SSS) according to various exemplary embodiments.

FIG. 6 illustrates four different exemplary SSB configurations that maybe used to implicitly indicate a part of the SSB index according tovarious exemplary embodiments.

FIG. 7 shows an example of an exemplary SSS interlaced resource element(RE) mapping pattern according to various exemplary embodiments.

FIG. 8 shows a table that includes various examples of different binaryscrambling codes that may be used to scramble the PSS or SSS accordingto various exemplary embodiments.

FIG. 9 shows an example of four different circuits that are each basedon a different primitive polynomial according to various exemplaryembodiments.

FIG. 10 shows a table that illustrates the value of v for PBCHscrambling according to various exemplary embodiments.

FIG. 11 shows an example of generating a reference symbol for PBCHtransmission according to various exemplary embodiments.

FIG. 12 shows an example of an extended master information block (MIB)payload according to various exemplary embodiments.

DETAILED DESCRIPTION

The exemplary embodiments may be further understood with reference tothe following description and the related appended drawings, whereinlike elements are provided with the same reference numerals. Theexemplary embodiments describe devices, systems and methods forimplementing various exemplary techniques related to a user equipment(UE) acquiring synchronization with a cell of a network viasynchronization signal blocks (SSBs).

The exemplary embodiments are described with regard to a UE. However,the use of a UE is merely for illustrative purposes. The exemplaryembodiments may be utilized with any electronic component that mayestablish a connection with a network and is configured with thehardware, software, and/or firmware to exchange information and datawith the network. Therefore, the UE as described herein is used torepresent any electronic component.

The exemplary embodiments are also described with regard to the UEcommunicating with a 5G New Radio (NR) network that is capable ofoperating in the unlicensed spectrum. However, reference to a 5G NRnetwork is merely provided for illustrative purposes. The exemplaryembodiments may apply to any type of network operating in the unlicensedspectrum.

The unlicensed spectrum is a shared transmission medium that may be usedby a plurality of different devices utilizing a plurality of differentcommunication protocols. Access to the unlicensed spectrum for 5G NRpurposes may implicate various regulations and/or standards. Forinstance, Listen-Before-Talk (LBT) may be implemented in accordance withthese regulations and/or standards to access the unlicensed spectrum forcommunications. LBT may relate to determining whether channels in theunlicensed spectrum are occupied by other signals prior to performing atransmission over the unlicensed spectrum.

In addition, the exemplary embodiments are further described with regardto a discovery reference signal (DRS) window. Generally, a DRS refers toa set of reference signals and/or synchronization signals transmitted bya cell. The contents of the DRS may be used by the UE for variousoperations such as, but not limited to, cell detection, cell searchprocedures, channel state information (CSI) detection, CSI measurement,beam selection, beam management and radio resource management (RRM). TheDRS may be transmitted periodically in a time window referred to as aDRS window. Each DRS window is configured to be a predetermined duration(e.g., 2 milliseconds (ms), 5 ms, 10 ms, etc.) and occur at apredetermined periodicity (e.g., 20 ms, 40 ms, 80 ms, 140 ms, etc.). Forexample, a DRS window of (x) ms may be scheduled to occur every (y) ms.However, any reference to DRS and a DRS window is merely provided forillustrative purposes, different entities may refer to similar conceptsby a different name.

A cell may transmit multiple SSBs within a DRS window. Those skilled inthe art will understand that an SSB may enable the UE to acquire timeand frequency synchronization with a cell. For example, a cell of the 5GNR network may periodically transmit multiple SSBs. Each SSB may includecontents such as, but not limited to, a physical cell ID (PCI), at leastone primary synchronization signal (PSS), at least one secondarysynchronization signal (SSS), at least one physical broadcast channel(PBCH) demodulation reference signal (DM-RS) and PBCH data. During acell search, the UE may receive one or more of the SSBs. The contents ofthe SSBs may enable the UE to acquire time and frequency synchronizationwith the cell.

In 5G NR, the cell may transmit up to (L) SSBs in a half frame, where(L) is dependent on the frequency range. The candidate SSBs in a halfframe may be indexed in ascending order in time from 0 to L−1. The UEmay determine the SSB index based on the configuration of the SSB. Forexample, when L is less than or equal to 8, the SSB index may bedetermined based on the detected PBCH DM-RS sequence. When L is greaterthan 8 and less than or equal to 64, the SSB index may be determinedbased on a combination of the detected PBCH DM-RS sequence and the PBCHpayload. The UE may establish cell timing based on the SSB index, thecandidate positions and/or the PBCH payload.

The exemplary embodiments relate to expanding the number of candidateSSB positions within a DRS window (e.g., L is greater than 64). This maybe implemented to account for LBT failure during SSB transmission. Inone aspect, the exemplary embodiments include implementing techniquesthat enable the UE to determine cell timing when the number of candidateSSB positions is expanded within the DRS window. In a second aspect, theexemplary embodiments describe a mechanism that allows a UE to determinethe quasi-co-location (QCL) assumptions for monitoring a controlresource set (CORESET) across different DRS windows.

FIG. 1 shows a network arrangement 100 according to various exemplaryembodiments. The network arrangement 100 includes the UE 110. Thoseskilled in the art will understand that the UE 110 may be any type ofelectronic component that is configured to communicate via a network,e.g., mobile phones, tablet computers, smartphones, phablets, embeddeddevices, wearable devices, Cat-M devices, Cat-M1 devices, MTC devices,eMTC devices, other types of Internet of Things (IoT) devices, etc. Anactual network arrangement may include any number of UEs being used byany number of users. Thus, the example of a single UE 110 is onlyprovided for illustrative purposes.

The UE 110 may be configured to communicate directly with one or morenetworks. In the example of the network arrangement 100, the UE 110 maywirelessly communicate with a 5G new radio (NR) radio access network (5GNR RAN) 120 and a wireless local access network (WLAN) 122. The 5G NRRAN 120 may be configured to operate in the unlicensed spectrum. The UE110 may also communicate with other types of networks (e.g., 5G cloudRAN, a next generation RAN (NG-RAN), an LTE RAN, a legacy RAN etc.). TheUE 110 may also communicate with networks over a wired connection.Therefore, the UE 110 may include a 5G NR chipset to communicate withthe 5G NR RAN 120 and an ISM chipset to communicate with the WLAN 122.

The 5G NR RAN 120 may be a portion of a cellular network that may bedeployed by a network carrier (e.g., Verizon, AT&T, T-Mobile, etc.). The5G NR RAN 120 may include, for example, cells or base stations (Node Bs,eNodeBs, HeNBs, eNBS, gNBs, gNodeBs, macrocells, microcells, smallcells, femtocells, etc.) that are configured to send and receive trafficfrom UEs that are equipped with the appropriate cellular chip set. TheWLAN 122 may include any type of wireless local area network (WiFi, HotSpot, IEEE 802.11x networks, etc.).

The UE 110 may connect to the 5G NR RAN 120 via a cell 120A. Thoseskilled in the art will understand that any association procedure may beperformed for the UE 110 to connect to the 5G NR RAN 120. For example,as discussed above, the 5G NR RAN 120 may be associated with aparticular network carrier where the UE 110 and/or the user thereof hasa contract and credential information (e.g., stored on a SIM card). Upondetecting the presence of the 5G NR RAN 120, the UE 110 may transmit thecorresponding credential information to associate with the 5G NR RAN120. More specifically, the UE 110 may associate with a specific cell(e.g., the cell 120A of the 5G NR RAN 120). As mentioned above, the useof the 5G NR RAN 120 is for illustrative purposes and any type ofnetwork may be used. For example, the UE 110 may also connect to theLTE-RAN (not pictured) or the legacy RAN (not pictured).

The cell 120A may be equipped with one or more communication interfaces.For example, the cell 120A may be equipped with a communicationinterface that is configured to communicate with UEs over the unlicensedspectrum. Further, the cell 120A may be configured with variousprocessing components that are configured to perform various operationssuch as, but not limited to, receiving signals from UEs and othernetwork components, processing received signals and generating signalsfor transmission. For example, the cell 120A may be equipped with one ormore processors. The processors may include one or more basebandprocessors and/or one or more applications processors. These processorsmay be configured to execute software and/or firmware. In anotherexample, the cell may be equipped with an integrated circuit with orwithout firmware. For example, the integrated circuit may include inputcircuitry to receive signals, processing circuitry to process thesignals and other information and output circuitry to output generatedsignals and information to other components (e.g., a communicationinterface, a transceiver, etc.). The functionality described herein forthe cell 120A may be implemented in any of these or other configurationsknown in the art for a cell of a network.

In addition to the networks 120 and 122 the network arrangement 100 alsoincludes a cellular core network 130. The cellular core network 130 maybe considered to be the interconnected set of components that managesthe operation and traffic of the cellular network. The networkarrangement 100 also includes the Internet 140, an IP MultimediaSubsystem (IMS) 150, and a network services backbone 160. The cellularcore network 130 also manages the traffic that flows between thecellular network and the Internet 140. The IMS 150 may be generallydescribed as an architecture for delivering multimedia services to theUE 110 using the IP protocol. The IMS 150 may communicate with thecellular core network 130 and the Internet 140 to provide the multimediaservices to the UE 110. The network services backbone 160 is incommunication either directly or indirectly with the Internet 140 andthe cellular core network 130. The network services backbone 160 may begenerally described as a set of components (e.g., servers, networkstorage arrangements, etc.) that implement a suite of services that maybe used to extend the functionalities of the UE 110 in communicationwith the various networks.

FIG. 2 shows an exemplary UE 110 according to various exemplaryembodiments. The UE 110 will be described with regard to the networkarrangement 100 of FIG. 1. The UE 110 may represent any electronicdevice and may include a processor 205, a memory arrangement 210, adisplay device 215, an input/output (I/O) device 220, a transceiver 225and other components 230. The other components 230 may include, forexample, an audio input device, an audio output device, a battery thatprovides a limited power supply, a data acquisition device, ports toelectrically connect the UE 110 to other electronic devices, sensors todetect conditions of the UE 110, etc.

The processor 205 may be configured to execute a plurality of enginesfor the UE 110. For example, the engines may include a cellsynchronization engine 235. The cell synchronization engine 235 mayperform various operations related to the UE 110 synchronizing with acell such as determining an SSB index and acquiring cell timing.

The above referenced engine each being an application (e.g., a program)executed by the processor 205 is only exemplary. The functionalityassociated with the engines may also be represented as a separateincorporated component of the UE 110 or may be a modular componentcoupled to the UE 110, e.g., an integrated circuit with or withoutfirmware. For example, the integrated circuit may include inputcircuitry to receive signals and processing circuitry to process thesignals and other information. The engine may also be embodied as oneapplication or separate applications. In addition, in some UEs, thefunctionality described for the processor 205 is split among two or moreprocessors such as a baseband processor and an applications processor.The exemplary embodiments may be implemented in any of these or otherconfigurations of a UE.

The memory 210 may be a hardware component configured to store datarelated to operations performed by the UE 110. The display device 215may be a hardware component configured to show data to a user while theI/O device 220 may be a hardware component that enables the user toenter inputs. The display device 215 and the I/O device 220 may beseparate components or integrated together such as a touchscreen. Thetransceiver 225 may be a hardware component configured to establish aconnection with the 5G NR-RAN 120 and the WLAN 122. Accordingly, thetransceiver 225 may operate on a variety of different frequencies orchannels (e.g., set of consecutive frequencies).

To synchronize with a 5G NR cell (e.g., cell 120A), the UE 110 mayacquire cell timing from an SSB. For example, the 5G NR cell maybroadcast SSB periodically over a particular frequency band using anyappropriate subcarrier spacing (SCS) (e.g., 15 kilohertz (Khz), 30 Khz,120 Khz, 240 Khz, etc.). When tuned to this frequency band, the UE 110may detect and decode the contents of the SSB to synchronize with the 5GNR cell. Those skilled in the art will understand that each SSB mayinclude content such as, but not limited to, a cell ID, a PSS, a SSS,PBCH data, master MIB, etc. However, any reference to an SSB or aparticular SSB configuration is merely provided for illustrativepurposes. The exemplary embodiments may utilize any appropriate type ofsynchronization information.

The cell 120A may transmit multiple SSBs within a DRS window. Asindicated above, the candidate SSBs in a half a frame (e.g., aconventional DRS window size) may be indexed in ascending order in timefrom 0 to L−1. The UE may determine the SSB index based on theconfiguration of the SSB. For example, when L is less than or equal to8, the SSB index may be determined based on the detected PBCH DM-RSsequence. When L is greater than 8 and less than or equal to 64, the SSBindex may be determined based on a combination of the detected PBCHDM-RS sequence and the PBCH payload. The UE 110 may establish celltiming based on the SSB index, the candidate positions and the PBCHpayload.

The exemplary embodiments are described with regard to an extended DRSwindow, an example of which is provided below with regard to FIG. 3. Theextended DRS window allows for more candidate SSB positions (e.g., L isgreater than 64) and thus, a larger SSB index (e.g., 7-bits or any otherappropriate size). The larger SSB index cannot be determined in theconventional manner. The exemplary embodiments described below includetechniques for determining the SSB index for the extended DRS window.

FIG. 3 shows illustrates an example of an exemplary DRS window accordingto various exemplary embodiments. The exemplary DRS window may beextended for a SCS (e.g., 120 Khz, 240 Khz, etc.) to (X) ms, where (x)is equal to 5*(N). In the example shown in FIG. 3, N is equal to 2 andthus, the exemplary DRS window is extended to 5*N=5*2=10 ms. In someembodiments, the maximum number of candidate SSB positions within a DRSwindow (Y) may be 128. For example, as shown in FIG. 3, the maximumnumber of candidate SSB positions may be 128 for a SCS of 120 Khz or 240Khz.

As mentioned above, the increase in candidate SSB positions may be usedto account for LBT failure. The following exemplary scenariosdemonstrate that when SSBs are dropped due to LBT failure, the SSB maybe cyclically wrapped around to the end of the burst set transmission.Exemplary scenario 305 shows LBT success occurring prior to SSBcandidate position 4 and a subsequent burst set transmission thatutilizes 64 SSB candidate positions. In addition, exemplary scenario 310shows LBT success occurring prior to SSB candidate position 8 and asubsequent burst set transmission that utilizes 64 SSB candidatepositions.

A variety of different techniques may be implemented to signal theextended SSB index. In one exemplary technique, the SSB index may beindicated via the DM-RS sequence of the PBCH. For instance, the cell120A may utilize the following scrambling sequence initialization(c_(init)) that incorporates the 7-bit SSB index. In this example, theSSB index is for 128 candidate SSB positions {0, . . . , 127} and isrepresented by l_(SSB) .

$c_{init} = {{2^{11}\left( {\overset{\_}{l_{SSB}} + 1} \right)\left( {\left\lfloor \frac{N_{ID}^{cell}}{4} \right\rfloor + 1} \right)} + {2^{6}\left( {\overset{\_}{l_{SSB}} + 1} \right)} + \left( {N_{ID}^{cell}{mod}4} \right)}$

In another exemplary technique, the SSB index may be included in the MIBpayload. In a further exemplary technique, the SSB index may be splitinto two parts. A first part of the SSB index may be signaled via theDM-RS sequence and a second part of the SSB index may be signaled viaPBCH payload. Thus, the SSB index may be split into two parts andjointly transmitted using DM-RS sequence and payload of PBCH channels,an example of which is illustrated in FIG. 4. In the example shown inFIG. 4, a first, second and third least significant bit (LSB) of the SSBindex (e.g., a(0), a(1), a(2)) is included in the DM-RS sequence and afourth, fifth, sixth and seventh LSB of the SSB index is included in thePBCH payload (e.g., a(3), a(4), a(5), a(6)). This technique provides areasonable tradeoff between UE complexity due to hypothetical detectionof a DM-RS sequence and the PBCH payload size and robustness.

In another exemplary technique, the SSB index may be split into threeparts. For example, a first part of the 7-bit SSB index may includethree bits (e.g., a(0), a(1), a(2)) that are signaled through differentPBCH DM-RS sequences. A second part of the 7-bit SSB index may includethree bits (e.g., a(3), a(4), a(5)) that are signaled in the PBCHpayload. Thus, in this example, signaling of the first part and thesecond part may be similar to the example shown in FIG. 4. However,unlike the example shown in FIG. 4, a third part of the 7-bit SSB indexmay include a bit (e.g., a(6)) that is implicitly signaled through theconfiguration of the SSS, PSS and/or PBCH. The exemplary embodimentsinclude a variety of different ways in which the third part of the SSBindex (e.g., a(6)) may be implicitly signaled to the UE 110. Specificexamples are provided in more detail below.

In some embodiments, signaling the third part (e.g., a(6) bit) of theSSB index may be based on the symbol location of the PSS and the SSS asshown in the table 500 of FIG. 5. Table 500 includes a first column 505that indicates whether the bit a(6) is 0 or 1. In addition, the tableincludes a second column 510 that indicates the orthogonal divisionfrequency multiplexing (OFDM) symbol number <x,y> relative to the startof an SSB, where x represents the PSS and y represents the SSS. Fourexemplary configurations are referenced in the table 500 (e.g., 605-620)and described in more detail below with regard to FIG. 6.

FIG. 6 illustrates four different exemplary SSB configurations that maybe used to implicitly indicate the third part of the SSB index (i.e.a(6)). FIG. 6 will be described with regard to the table 500 of FIG. 5.In this example, a first configuration 605 may be used to indicate thata(6) is 0. The configuration 605 includes the PSS at symbol index 0 andthe SSS at symbol index 2 i.e. pair of <0,2> in FIG. 5. Thus, when theUE 110 identities configuration 605 <0,2> for PSS and SSS, it mayimplicitly determine that a(6) is equal to ‘0’ in accordance to FIG. 5.

In this example, three different configurations 610, 615 and 620 may beused to indicate that a(6) is 1. The configuration 610 includes the SSSat symbol index 0 and the PSS at symbol index 2. Compared toconfiguration 605, configuration 610 swaps the location of the PSS andthe SSS. Thus, when the UE 110 identities configuration 610, it mayimplicitly determine that a(6) is equal to ‘1’.

The configuration 615 includes the SSS at symbol index 1 and the PSS atthe symbol index 3. Note that the symbol index ‘0’ is defined as thefirst symbol of SSB transmission. Compared to configuration 605,configuration 615 relocates the PSS from symbol index 0 to symbol index3. Thus, when the UE 110 identities configuration 615, it may implicitlydetermine that a(6) is equal to ‘1’.

The configuration 620 includes the PSS at symbol index 1 and the SSS atsymbol index 3. Compared to the configuration 605, configuration 620right shifts the PSS and SSS by two symbols. Thus, when the UE 110identities configuration 620, it may implicitly determine that a(6) isequal to ‘1’.

In some embodiments, the a(6) value may be indicated by different cyclicshifts of the PSS. The cyclic shifts may be represented by the followingequation:

d _(pss)(n)=1−2(m)

When a(6) is 0, m may be represented as:

(n+43N _(ID) ⁽²⁾)mod 127

When a(6) is 1, m may be represented as:

(n+k(N _(ID) ⁽²⁾−1)+43)mod 127

In this example, k may equal 21

$\left( {{e.g.},\left\lfloor \frac{43}{2} \right\rfloor} \right).$

Thus, depending on the PSS cyclic shift, the UE 110 may infer the valueof a(6).

In other embodiments, the a(6) value may be indicated by differentcyclic shifts of the SSS. The cyclic shift may be represented by thefollowing equation when a(6) is 0:

d _(sss)(n)=[1−2x ₀((n+m ₀)mod 127)][1−2x ₁((n+m ₁)mod 127)]

The cyclic shift may be represented by the following equation when a(6)is 1:

d _(sss)(n)=[1−2x ₀((n+m ₀ +N)mod 127)][1−2x ₁((n+m ₁)mod 127)]

In this example, N may equal

${{f(127)}\left\lfloor \frac{127}{2} \right\rfloor} = 63.$

Thus, depending on the SSS cyclic shift, the UE 110 may infer the valueof a(6).

In some embodiments, different maximum length sequences (m-sequences)are defined for the SSS to signal. For example, a first m-sequence maybe used to indicate a(6) is 1 and a second different m-sequence may beused to indicate a(6) is 0.

In other embodiments, the value of a(6) may be signaled by different SSSresource element (RE) mapping patterns. For example, if a(6) is 0, thegenerated sequence of symbols d_(sss)(0), . . . , d_(sss)(126) may besequentially mapped to RE(k,l) in increasing order of k, where krepresents the frequency index and l represents the time index,respectively. If a(6) is 1, the generated sequence of symbolsd_(sss)(0), . . . , d_(sss)(126) may be first interleaved and thensequentially mapped to RE(k,l) in increasing order of k. Thus, aninterlaced (e.g., interleaved) mapping pattern may be used to indicatethat a(6) is 1. FIG. 7 shows an example of an exemplary SSS interlacedRE mapping pattern.

In some embodiments, the PSS or SS sequence is scrambled with a binaryscrambling code c(n) which may be represented by the following equation:

c(n)={tilde over (c)}((n+a(6))mod 127)

In this example, {tilde over (c)} is generated from different primitivepolynomials. FIG. 8 shows a table 800 that includes various examples ofdifferent binary scrambling codes that may be used to scramble the PSSor SSS. FIG. 9 shows an example of four different circuits 910-940 thatare each based on a different primitive polynomial. Circuit 910 is basedon 137 of table 800, circuit 920 is based on 157 of table 800, circuit930 is based on 203 of table 800 and circuit 940 is based on 253 oftable 800.

In some embodiments, a(6) may be carried by frozen bits of a PBCH polarcode. When a(6) is carried by frozen bits, it is not part of input tothe cyclic redundancy check (CRC) encoding and the CRC bits are not afunction of a(6). Thus, at the cell 120A, CRC encoding is performed andthen polar encoding is performed to incorporate a(6) into the SSB thatis to be transmitted.

In other embodiments, a(6) may be carried by the selection of scramblingsequence [W₀, W₁, . . . W₂₃] to scramble the CRC bits of the PBCH. Whena(6) is 0, the scrambling sequence [W₀, W₁, . . . W₂₃] may be [0, 0, . .. 0]. When a(6) is 1, the scrambling sequence [W₀, W₁, . . . W₂₃] may be[1, 1, . . . 1].

In some embodiments, a(6) is carried by a scrambling sequence prior toCRC attachment and encoding process. For example, the scramblingsequence may be based on a selection of value v to determine the segmentof long gold sequence C. FIG. 10 shows a table 1000 that illustrates thevalue of v for PBCH scrambling.

In other embodiments, a(6) value may be modulated to generate a singlemodulation symbol d(0). This modulation symbol may be used in thegenerate of the reference symbol for PBCH transmission. FIG. 11 shows anexample of generating a reference symbol for PBCH transmission.

In some embodiments, the candidate SSB index may be separately encodedwith a CRC attachment. This may be performed at a low rate to ensurerobustness. To minimize signaling overhead, the CRC may be short inlength (e.g., 8-bit). In addition, the candidate SSB index block (CSSIB)may be mapped to a predefined set of RSs to facilitate neighbor cellmeasurement. Further, the resource partition between a legacy MIB andthe CSSIB may be hard encoded or implementing via linearly splittingbased on the payload of the MIB and CSSIB payload. For example, CSSIBsymbols may be mapped with the frequency region corresponding to thePSS/SS. This allows the UE to operate with the bandwidth same as thePSS/SS bandwidth for inter-frequency neighbor cell measurement.

As mentioned above, in a second aspect, the exemplary embodimentsdescribe a mechanism that allows a UE to determine the QCL assumptionsfor monitoring a CORESET across different DRS windows. In someembodiments, a set of Q values may be defined in standards (e.g., 3GPPstandards) depending on the frequency range. The Q value may representthe number of SSBs and/or SSB candidate positions that may be used forSSB transmission. For example, above 6 gigahertz (Ghz) a set of Q valuesmay be defined as {8, 16, 32, 64}.

In some embodiments, the Q value may be indicated as part of an extendedMIB payload. FIG. 12 shows an example of an extended MIB payload. Forexample, the rel-15 MIB payload may be extended to indicate the Q value,where M_(Q)=log₂n and where n denotes the number of supported Q values.

In other embodiments, the Q value may be indicate by re-interpretingcertain field in the legacy MIB. For example, the UE 110 may assume thesame numerologies for the SSB and CORESET 0. Consequently, the UE 110may interpret the following two information element (IEs) of rel-15 MINfor providing the Q value. In one configuration, the IEssbSubcarrierSpacingCommon (1-bit) and the LSB of IE ssb-SubarrierOffset(1-bit) may be configured by the cell 120A to indicate the Q value tothe UE 110. In another configuration, the IE ssbSubcarrierSpacingCommon(1-bit) and spare bit (1-bit) may be configured by the cell 120A toindicate the Q value to the UE 110.

In further embodiments, the Q value may be indicated as part of thesystem information block (SIB). For example, the cell 120A may configurethe SIB to include an indication of the Q value.

Those skilled in the art will understand that the above-describedexemplary embodiments may be implemented in any suitable software orhardware configuration or combination thereof. An exemplary hardwareplatform for implementing the exemplary embodiments may include, forexample, an Intel x86 based platform with compatible operating system, aWindows OS, a Mac platform and MAC OS, a mobile device having anoperating system such as iOS, Android, etc. The exemplary embodiments ofthe above described method may be embodied as a program containing linesof code stored on a non-transitory computer readable storage mediumthat, when compiled, may be executed on a processor or microprocessor.

Although this application described various embodiments each havingdifferent features in various combinations, those skilled in the artwill understand that any of the features of one embodiment may becombined with the features of the other embodiments in any manner notspecifically disclaimed or which is not functionally or logicallyinconsistent with the operation of the device or the stated functions ofthe disclosed embodiments.

It is well understood that the use of personally identifiableinformation should follow privacy policies and practices that aregenerally recognized as meeting or exceeding industry or governmentalrequirements for maintaining the privacy of users. In particular,personally identifiable information data should be managed and handledso as to minimize risks of unintentional or unauthorized access or use,and the nature of authorized use should be clearly indicated to users.

It will be apparent to those skilled in the art that variousmodifications may be made in the present disclosure, without departingfrom the spirit or the scope of the disclosure. Thus, it is intendedthat the present disclosure cover modifications and variations of thisdisclosure provided they come within the scope of the appended claimsand their equivalent.

What is claimed:
 1. A baseband processor configured to performoperations comprising: monitoring a frequency band during a discoveryreference signal (DRS) window for a synchronization signal block (SSB)transmitted by a cell of the network; determining an SSB index based oninformation received from the cell of the network; and synchronizingwith the cell based on the SSB index.
 2. The baseband processor of claim1, wherein the SSB index is a 7-bit SSB index corresponding to more than64 SSB candidate positions.
 3. The baseband processor of claim 2,wherein the SSB index is included in a demodulation reference signal(DM-RS) sequence of a physical broadcast channel (PBCH).
 4. The basebandprocessor of claim 1, wherein a first part of the SSB index is includedin a demodulation reference signal (DM-RS) sequence and a second part ofthe SSB index is included in a physical broadcast channel (PBCH)payload.
 5. The baseband processor of claim 4, wherein a third part ofthe SSB index is indicated by a scrambling sequence used to scramble acyclic redundancy check (CRC) bits of the PBCH.
 6. The basebandprocessor of claim 4, wherein a third part of the SSB indicated based ona symbol location of a primary synchronization signal (PSS) and asecondary synchronization signal (SSS), wherein the symbol location isbased on a symbol index defined relative to a start of the SSB.
 7. Thebaseband processor of claim 4, wherein a third part of the SSB isindicated by a cyclic shift of a primary synchronization signal (PSS) ora cyclic shift of a secondary synchronization signal (SSS).
 8. Thebaseband processor of claim 4, wherein a third part of the SSB isindicated by a maximum length sequences (m-sequence) used for asecondary synchronization signal (SSS).
 9. The baseband processor ofclaim 4, wherein a third part of the SSB is indicated by a sequence ofsymbols sequentially mapped to a resource element in increasing order offrequency index.
 10. The baseband processor of claim 4, wherein a thirdpart of the SSB is indicated by an interlaced mapping pattern.
 11. Thebaseband processor of claim 4, wherein a third part of the SSB isindicated by a primary synchronization signal (PSS) or a secondarysynchronization signal (SSS) scrambled with a binary scrambling code.12. The baseband processor of claim 4, wherein a third part of the SSBis indicated by frozen bits of PBCH polar code.
 13. The basebandprocessor of claim 4, wherein a third part of the SSB is carried by ascrambling sequence utilized prior to cyclic redundancy check (CRC)attachment.
 14. The baseband processor of claim 4, wherein a third partof the SSB is based on a single modulation symbol used in the generationof the reference symbol for PBCH transmission.
 15. A user equipment(UE), comprising: a transceiver configured to communicate with multiplenetworks; and a processor communicatively coupled to the transceiver andconfigured to perform operations comprising: monitoring a frequency bandduring a discovery reference signal (DRS) window for a synchronizationsignal block (SSB) transmitted by a cell of the network; determining anSSB index based on information received from the cell of the network;and synchronizing with the cell based on the SSB index.
 16. The UE ofclaim 15, wherein a number of SSBs to be transmitted is indicated by anextended master information block (MIB) payload.
 17. The UE of claim 16,wherein a number of SSBs to be transmitted is indicated by a firstinformation element (IE) and a second IE included in a masterinformation block (MIB).
 18. The UE of claim 16, wherein a number ofSSBs to be transmitted is indicated by a system information block (SIB).19. The UE of claim 18, wherein the SSB index is included in a masterinformation block (MIB) payload.
 20. The UE of claim 15, wherein a firstpart of the SSB index is included in a demodulation reference signal(DM-RS) sequence and a second part of the SSB index is included in aphysical broadcast channel (PBCH) payload.